1. Field of the Invention
The present invention relates to a refrigeration system adapted for use in ice making machines, refrigerators or the like.
2. Discussion of the Prior Art
In the refrigeration sytem of a conventional ice making machine disclosed in Japanese Utility Model Publication No. 60-13023, a solenoid value of the normally closed type is disposed within a bypass line of the refrigerant circulation circuit to supply therethrough the hot gas outflowing from the refrigerant compressor directly into the evaporator when the solenoid valve has been energized. Such an arrangement of the solenoid valve is useful to dissolve the external surfaces of frozen ice cubes for removal of them during the defrost cycle. It is, however, observed that during the freezing cycle prior to the defrost cycle, frost or ice is grown or formed on outer surfaces of the evaporator to lower temperature of the evaporator. The lowering in temperature of the evaporator decreases an opening degree of an expansion valve to decrease an amount of refrigerant flowing into the evaporator. As a result, flow velocity of refrigerant within the evaporator lowers, and confinement of liquefied refrigerant is facilitated within the evaporator. When accumlated in the evaporator, the liquefied refrigerant is rapidly and concentrically pushed out by the hot gas with high velocity and large amount flowing out from the compressor through the solenoid valve and circulated into the compressor. This results in shortening in life of the compressor and undesired noises caused by hammering the interior of the compressor with the circulated liquefied refrigerant.
In the case that an accumulator is disposed in a line between the evaporator and compressor to store the liquefied refrigerant flowing therein from the evaporator, the amount of gaseous refrigerant to be circulated into the compressor will decrease in accordance with an increase of the liquefied refrigerant in the accumulator. This results in deterioration of the freezing performance of the ice making machine. Furthermore, it is required that for proper restraint in an amount of liquefied refrigerant circulated into the compressor, the accumulator has a large capacity. However, such an arrangement of the accumulator results in an increase of manufacturing cost of the refrigeration system.